Originally quality means fitness for use. Quality inevitably becomes one of the properties of the product once the product is in exchange and in use. In modern definition, quality is inversely proportional to variability. The aim of quality masters' such as Shewhart Deming, and Taguchi's pioneer work on using statistical methods for quality control and improvement justifies this definition: looking for consistency. In fact, while modern production methods are mainly to enhance productivity, they often have the effect of reducing variability of the products. For example, in late nineteenth century Frederick Taylor divided work in mass production into tasks so that not only the products could be manufactured and assembled more easily and more efficiently, but also the standardized production and assembly methods reduced the variability of the product-a positive impact on quality.